脊髓背角HCN通道在神经病理性疼痛中的作用

目的:观察脊髓背角超极化激活环核苷酸门控阳离子通道(HCN通道)在坐骨神经缩窄性损伤(CCI)所致的慢性神经病理性疼痛中的作用。方法:8周龄成年雄性SD大鼠48只随机分为6组:(1)sham组(假手术组)、(2)CCI组(鞘内注射生理盐水)、(3)~(6)ZD7288+CCI(鞘内分别注射1,10,30,50μg ZD7288),每组8只。CCI及CCI+ZD7288组大鼠在鞘内置管5 d后行CCI术,术后鞘内给药,每日两次,连续14 d;sham组大鼠不进行鞘内置管,仅游离坐骨神经,不结扎。分别于CCI术前1 d,术后1、3、5、7、10、14 d鞘内给药2 h后测定热缩足潜伏期(TWL);术后第7、14 d处死大鼠,取术侧L4~L6脊髓背角,采用Western Blot技术检测脊髓背角HCN1,3,4及磷酸化蛋白激酶A(P-PKA)表达的变化。结果:大鼠CCI术后即形成稳定的热痛敏,TWL明显缩短;与CCI组相比,鞘内给予HCN通道阻滞剂ZD7288可明显延长CCI大鼠的TWL(P0.05)。Western Blot结果显示,与假手术组相比,CCI组大鼠在术后7、14 d术侧脊髓背角HCN1,3,4及P-PKA表达显著增加(P0.05);鞘内给予ZD7288可显著降低CCI大鼠HCN1,3,4及P-PKA的表达(P0.05)。结论:脊髓背角HCN通道的激活可促进CCI所致的神经病理性痛的发生与维持,HCN通道阻滞剂ZD7288具有良好的镇痛效应,ZD7288的镇痛作用可能与其抑制PKA的活性密切相关。     

ClC-3在神经病理性痛大鼠脊髓背角及背根神经节的表达及其参与痛行为调控的研究

目的:观察电压门控性氯通道(voltage-gated chloride channel,ClC)3型在腓总神经结扎神经病理性痛模型大鼠脊髓背角(spinal dorsal horn,SDH)和背根神经节(dorsal root ganglion,DRG)内的表达变化及阻断氯离子通道后痛行为的改变。方法:应用免疫组织化学染色法、蛋白印迹法以及痛行为检测观察ClC-3在神经病理性痛大鼠SDH和DRG的变化和作用。结果:在正常大鼠,ClC-3主要位于DRG神经元胞膜;在SDH,ClC-3阳性纤维主要位于Ⅰ层。在腓总神经结扎大鼠,1周内结扎侧背角Ⅰ层及DRG的ClC-3表达增加,2～4周表达逐渐减少,在DRG也观察到相同的现象。给予氯离子通道阻断剂后,腓总神经结扎大鼠的痛阈下降。结论:ClC-3在神经病理性痛早期表达上调,随病程发展逐渐下降;阻断ClC-3可使大鼠痛阈下降。     

曲古抑菌素A通过抑制脊髓背角内的炎症反应减轻大鼠神经病理性痛

目的:观察曲古抑菌素A (TSA)对脊神经结扎(SNL)大鼠镇痛效果及分子机制。方法:40只健康雄性Sprague Dawley(SD)大鼠随机分为假手术组(sham)、曲古抑菌素A处理组(TSA)、脊神经结扎组(SNL)和SNL+TSA组(SNL+TSA)。采用L5脊神经结扎(SNL)的方法建立神经病理性痛模型,鞘内注射TSA进行干预,通过von Frey丝和热板实验检测大鼠的痛敏,应用免疫荧光染色方法观察大鼠脊髓背角内HDAC1的表达情况;应用Western Blot方法观察大鼠脊髓背角内胶质纤维酸性蛋白(GFAP)和离子钙接头蛋白分子1(Iba-1)的表达水平;应用real time RT-PCR方法检测大鼠脊髓背角内TNF-α、IL-1β和IL-6的mRNA表达水平。结果:SNL模型大鼠术后机械性痛阈值和热痛阈值均显著降低(P <0.05),鞘内给予TSA能够明显缓解大鼠患侧后足机械性痛敏和热痛敏; SNL模型大鼠脊髓背角内HDAC1的表达较对照组明显增加,而鞘内注射TSA可显著抑制其表达; SNL术后脊髓背角内GFAP和Iba-1的表达显著升高(P <0.05),...     

脊髓背角和背根神经节ERK1/2磷酸化表达在鞘内注射高乌甲素抗大鼠神经病理性疼痛中的作用

目的探讨鞘内注射高乌甲素对神经病理性疼痛大鼠脊髓背角和背根神经节ERK1/2磷酸化(p-ERK1/2)表达的影响。方法将90只SD大鼠随机分为假手术组(S组)、手术组(O组)和高乌甲素(L组)(n=30),建立坐骨神经慢性压迫(chronic constriction injury of sciatic nerve,CCI-SN)模型,术后L组鞘内注射高乌甲素20μg/kg,S组和O组以同样方式注射等体积生理盐水,末次给药后每组又分为术后第4、7和10天三个亚组(n=10);分别于相应时间点测定大鼠机械刺激缩足阈值(paw withdrawal mechanical threshold,PWMT),并采用Western blot技术检测脊髓背角和背根神经节p-ERK1/2的表达。结果与S组相比,O组术后第4、7和10天PWMT值均显著降低(第4、7天:P0.001;第10天:P0.01)。与O组相比,L组术后第4、7和10天PWMT值均明显升高(第4、7天:P0.05;第10天:P0.01)。在脊髓背角和背根神经节中,O组术后第4、7和10天p-ERK1/2表达均明显高于相应S组(脊髓背角:第4、7天,P0.001;第10天,P0.01;背根神经节:第4、10天,P0.01;第7天,P0.001);与O组相比,L组p-ERK1/2水平明显降低(脊髓背角:第4、10天,P0.05;第7天,P0.01;背根神经节:第4、7天,P0.05;第10天,P0.01)。结论鞘内注射高乌甲素能有效缓解CCI-SN大鼠神经病理性疼痛,其机制可能与其抑制脊髓背角和背根神经节中p-ERK1/2的表达有关。     

鞘内注射丹参酮ⅡA对坐骨神经慢性压迫性痛大鼠脊髓背角内磷酸化p38MAPK的影响

目的:研究丹参酮ⅡA(TSA)对坐骨神经慢性压迫性痛大鼠脊髓背角内磷酸化p38丝裂原活化蛋白激酶(p-p38MAPK)表达的影响,探讨丹参酮ⅡA的镇痛机制。方法:SD雄性大鼠随机分为假手术组(sham组)和模型组。模型组又分为生理盐水组(NS组)和处理组(TSA组)。模型组在手术当日及术后每日鞘内注射生理盐水0.1 ml和丹参酮ⅡA20 mg/kg,连续注射10 d。检测各组大鼠在手术前及术后10 d的机械痛阈和热痛阈;术后第10天,免疫组织化学和免疫蛋白印迹检测大鼠脊髓背角内p-p38MAPK的表达。结果:与假手术组比较,生理盐水组大鼠的机械痛阈和热痛阈明显降低,p-p38MAPK的表达增多;与生理盐水组比较,处理组的机械痛阈和热痛阈明显升高,脊髓背角内p-p38MAPK的表达下降,差异均有统计学意义。结论:鞘内注射丹参酮ⅡA对坐骨神经慢性压迫性痛模型大鼠的镇痛作用可能与降低脊髓背角内p-p38MAPK的表达有关。     

脊髓刺激术对神经病理性痛模型大鼠痛行为和脊髓背角内小胶质细胞激活的影响

目的:探讨脊髓刺激术(spinal cord stimulation,SCS)对神经病理性痛(neuropathic pain,NP)模型大鼠痛行为及脊髓背角内小胶质细胞激活的影响。方法:成年大鼠20只,随机分为4组:(1)正常对照组(control组);(2)SCS组:正常大鼠给予SCS刺激;(3)脊神经结扎(spinal nerve ligation,SNL)假刺激组(SNL+shamSCS组):SNL且植入SCS装置,但不刺激;(4)SNL+SCS组:SNL且给予SCS刺激。术前连续3 d、术后第5 d检测各组大鼠足底机械痛敏阈值(mechanical withdrawal threshold,MWT)。SCS组和SNL+SCS组术后第2-5 d给予SCS刺激,每d持续8 h;且在每次给予SCS 8 h刺激前进行90 min行为学测试,即SCS刺激30 min,以及刺激结束后的60 min内(共90 min),每15 min测量一次MWT。在第5 d给予SCS 8 h刺激结束后处死动物,利用免疫组织化学染色结合平均光密度(average optical density,AOD)分析的方法检测各组大鼠腰5节段脊髓背角内小胶质细胞特异性标志物OX-42的表达情况。结果:(1)行为学结果显示:术后第5 d,SNL+shamSCS组和SNL+SCS组大鼠手术侧后爪的MWT由术前26.00±0.0 g分别降至5.50±0.96 g和6.40±0.40 g(P<0.05);SNL+SCS组给予SCS刺激30 min后大鼠手术侧后爪的MWT明显有所提高,达16.20±2.60 g,与刺激前(6.40±0.40 g)相比有显著性差异(P<0.05);但停止SCS刺激60 min后,大鼠的MWT明显有所下降,与刺激前几乎没有明显差别。(2)免疫组化染色结果显示:术后第5 d,SNL+SCS组脊髓背角内OX-42的表达明显弱于SNL+shamSCS组,但二者都强于control组和SCS组;AOD结果也证实:SNL+SCS组大鼠脊髓背角内OX-42的AOD(1.29±0.28)明显低于SNL+shamSCS组(2.66±0.38),但仍高于control组(0.14±0.21)和SCS组(0.24±0.08)。结论:SCS对SNL模型大鼠的神经病理性痛有较好的镇痛效果;该作用可能与SCS刺激显著抑制脊髓背角内小胶质细胞的激活密切相关。     

鞘内注射丹参酮ⅡA对坐骨神经慢性压迫大鼠脊髓背角c-fos表达的影响

目的研究丹参酮ⅡA对坐骨神经慢性压迫大鼠脊髓背角内c-fos蛋白的表达,探讨丹参酮ⅡA(TanshinoneⅡA,TSA)的镇痛机制。方法 30只SD雄性大鼠随机分为假手术组(sham组,n=10)和模型组(n=20)。模型组又分为生理盐水组(NS组)和处理组(TSA组,n=10)。模型组在手术当日及术后每日在模型大鼠鞘内注射生理盐水0.1 m L和丹参酮ⅡA20 mg/kg,连续注射14 d。检测各组大鼠在手术前及术后14 d的机械痛阈和热痛阈;术后第14天,免疫组织化学法检测大鼠脊髓背角内c-fos的表达。结果与假手术组比较,生理盐水组大鼠的机械痛阈和热痛阈明显降低,c-fos的表达增多;与生理盐水组比较,处理组的机械痛阈和热痛阈明显升高,脊髓背角内c-fos的表达下降,差异均有明显统计学意义。结论鞘内注射丹参酮ⅡA对坐骨神经慢性压迫模型大鼠的镇痛作用可能与降低脊髓背角内c-fos的表达有关。     

谷氨酰胺合成酶在神经病理性疼痛大鼠脊髓背角的表达

目的:检测谷氨酰胺合成酶(GS)在保留性坐骨神经分支选择性结扎模型(SNI)大鼠脊髓背角的表达与定位,并探讨其在神经病理性疼痛中的作用机制。方法:48只雄性SD大鼠随机分为假手术组(sham组)和SNI组。两组大鼠分别于术前1 d、术后1、3、7和14 d测量机械痛域(PWT),并于术后相应时间点处死,采用Western Blot检测L_4-6节段脊髓组织中GS、p-p38、IL-10和TNF-α的表达情况;免疫荧光观察脊髓背角GS的表达与定位情况。结果:与sham组相比,SNI组大鼠PWT于术后1 d开始降低(P <0.05),术后3、7和14 d出现明显差异(P <0.05),模型制备成功。术后3 d和7 d,SNI组大鼠脊髓背角GS、TNF-α和p-p38表达量较sham组明显增高(P <0.05); IL-10表达逐渐下降,在术后7 d和14 d有统计学差异(P <0.05)。结论:GS高表达并主要定位于脊髓背角的星形胶质细胞,GS可能通过p38 MAPK通路参与神经病理性疼痛中的炎症因子的调控。     

坐骨神经选择性损伤痛模型小鼠脊髓背角线粒体解偶连蛋白UCP4的表达变化

目的:观察线粒体保护蛋白解偶联蛋白4(uncoupling protein 4,UCP4)在坐骨神经选择性损伤(sparednerve injury,SNI)模型小鼠脊髓背角中的表达变化。方法:健康C57BL/6小鼠分为假手术对照组(n=21)和坐骨神经分支选择性损伤SNI组(n=21),实验组损伤后饲养3,7,14 d。行为学采用测定小鼠热痛阈和Von Frey机械性痛阈;用免疫荧光组织化学染色法检测对比小鼠脊髓L3-6节段背角内UCP4免疫阳性细胞的数量。结果:SNI术后3 d,小鼠手术侧热痛阈和机械性痛阈明显低于假手术组,术后14 d达最低值。UCP4分布于正常小鼠脊髓背角,SNI后3 d损伤组小鼠脊髓背角中的UCP4表达降低,图像分析表明UCP4的光密度与对照组比较,差异有统计学意义(P<0.05);脊髓背角中UCP4的表达在14 d时其降低程度最明显,图像分析表明光密度与对照组、3d和7 d比较,差异均有统计学意义(P<0.05)。结论:SNI后脊髓背角线粒体保护蛋白UCP4表达降低可能参与神经病理性疼痛的中枢敏化过程。     

鞘内注射甘珀酸降低CX43的表达对大鼠镜像痛的影响

目的:研究大鼠脊髓星形胶质细胞CX43的表达变化及对镜像痛的影响。方法:96只SD大鼠随机分为四组:Sham组,SNI组,SNI+NS组,SNI+CBX组,每组24只。各组分别于术前l d、术后3、7、10、l4和21 d观察大鼠疼痛行为学变化,其中Sham组,SNI组于术后14 d采用免疫组化法分析缝隙连接蛋白43(Cx43)、胶质原纤维酸性蛋白(GFAP)的表达情况;SNI+CBX组于术后第5~9 d鞘内注射甘珀酸10μl(20μg),SNI+NS组注射等量生理盐水,并于术后10、14和21 d三个时间点采用Western Blot的方法检测脊髓内CX43蛋白表达情况,采用免疫组化法分析GFAP的表达变化情况。结果:SNI组与Sham组相比,行为学上大鼠双侧机械缩足阈值降低,脊髓星形胶质细胞CX43及GFAP表达增加(P0.05);SNI+CBX组与SNI+NS组相比,Western Blot显示CX43表达降低,免疫组化显示脊髓背角双侧GFAP表达降低(P0.05),术后14 d,21 d大鼠双侧机械缩足阈值升高。结论:鞘内注射甘珀酸降低CX43的表达可抑制星形胶质细胞的活化,并缓解大鼠双侧的机械痛。     

Spinal cord stimulation induces c-Fos expression in the dorsal horn in rats with neuropathic pain after partial sciatic nerve injury

Spinal cord stimulation (SCS) is an established treatment for intractable neuropathic pain, especially CRPS-1. The mechanisms of action of SCS have only been partly elucidated and include suppression of the hyper-excitability of the Wide Dynamic Range neurons and a GABA increase in the dorsal horn. In the present study we demonstrate an increase of c-Fos immunoreactive cells in the dorsal horn after SCS, suggesting early cellular activation that may preclude earlier described electrophysiological and biochemical changes in the dorsal horn after SCS. In a rat model of neuropathic pain, allodynia was induced and quantified using the von Frey test. In 11 rats a SCS device was implanted and spinal cord stimulation performed. Withdrawal threshold were measured every 15 min up to 90 min. A sham group (n = 6) also had a SCS device implanted, but did not receive SCS. After SCS the animals were perfused and histology was performed for quantification of c-Fos immunoreactivity in the dorsal horns. We found a significant increase in c-Fos in the SCS group compared to our sham group and control tissue, indicating late cellular activity in the dorsal horn after SCS.     

Role of spinal cholecystokinin in neuropathic pain after spinal cord hemisection in rats

In the present study we determined whether spinal cholecystokinin (CCK) or the cholecystokinin receptor is involved in below-level neuropathic pain of spinal cord injury (SCI). The effect of the CCK_B receptor antagonist, CI-988 on mechanical allodynia and the expression level of CCK and CCK_B receptor were investigated. Spinal hemisection was done at the T13 level in rats under enflurane anesthesia. CI-988 was administered intraperitoneally and intrathecally and behavioral tests were conducted. After systemic injection, mechanical allodynia was reduced by higher doses of CI-988 (10 and 20 mg/kg). Intrathecal CI-988 (100, 200 and 500 μg) dose-dependently increased the paw withdrawal threshold in both paws. Following spinal hemisection, CCK mRNA expression increased on the ipsilateral side at the spinal segments caudal to the injury and both sides of the spinal L4-5 segments without any significant changes in CCK_B receptor mRNA levels. These results suggest that up-regulation of spinal CCK may contribute to maintenance of mechanical allodynia following SCI and that clinical application of CI-988 or similar drugs may be useful therapeutic agents for management of central neuropathic pain.     

Plasticity in the synaptic number associated with neuropathic pain in the rat spinal dorsal horn: A stereological study

This study aimed to determine whether neuropathic pain is associated with a plasticity change in the number of synapses in the spinal dorsal horn. 12 normal adult SD rats were randomly divided into two groups: 7 animals were subjected to unilateral loose ligation (to induce chronic constriction injury) of the sciatic nerve (CCI group) and 5 animals subjected to unilateral sham-operation (sham-operated group). 28 days after operation, the L4–L6 segment of the spinal cord was removed, and paraffin-embedded sections were prepared and stained with Nissl's method and synaptophysin immunohistochemistry. The numbers of neurons and synapses in the spinal dorsal horn were estimated using a contemporary stereological technique—the optical disector. An 86% increase in the number (per unit length of the spinal cord) of synapses or 98% increase in the ratio between the numbers of synapses and neurons in the spinal dorsal horn was found in the middle tissue block but not in both the rostral and caudal tissue blokes cut from L4–L6 segment of the spinal cord. The results suggest that neuropathic pain, as established by the CCI model, is associated with a plasticity change in the spinal dorsal horn: increase in the number of synapses.     

Dexmedetomidine decreases hyperalgesia in neuropathic pain by increasing acetylcholine in the spinal cord

The activation of α2-adrenoceptors has attracted attention as a therapeutic target for neuropathic pain, which remains a clinical challenge. In the present study, we examined the interaction between α2-adrenergic and cholinergic signaling in a rat model of neuropathic pain induced by spinal nerve ligation (SNL). Intrathecal administration of dexmedetomidine, which is a selective α2-adrenoceptor agonist (0.1–1.0 μg), dose-dependently suppressed hyperalgesia in SNL rats but did not alter paw withdrawal thresholds in normal rats. The analgesic effect of dexmedetomidine was abolished by intrathecal pretreatment with idazoxan (30 μg) and atropine (30 μg), which antagonize the α2-adrenoreceptor and muscarinic receptor, respectively. In vivo microdialysis in the lumbar spinal dorsal horn revealed that acetylcholine concentrations increased after dexmedetomidine perfusion (1 μM), but only in SNL rats. The combination of an ineffective dose of intrathecal dexmedetomidine with intraperitoneal donepezil, which is a cholinesterase inhibitor, decreased neuropathic hypersensitivity. These results suggest that plasticity of the spinal noradrenergic–cholinergic axis only occurs in neuropathic pain states. Thus, drug combinations that strengthen the noradrenergic–cholinergic interaction may provide therapeutic benefit in neuropathic pain.     

穴位电针对慢性神经病理性疼痛大鼠脊髓前列腺酸性磷酸酶表达的影响

目的 观察电针对神经病理性痛大鼠脊髓前列腺酸性磷酸酶（PAP）的表达,及腺苷含量及大鼠痛阈变化的影响,探讨电针镇痛机制。方法 21只雄性SD大鼠采用慢性坐骨神经压缩模型(CCI),取“足三里”及“太冲”穴。设假手术组（sham组）、模型组(CCI组）和电针治疗组（EA组）。采用行为学检测大鼠术前、术后第7天和电针治疗后大鼠机械痛敏值和热敏痛阈值变化,采用Real-time PCR技术检测脊髓PAP mRNA的表达,高效液相色谱法检测脊髓腺苷含量。结果 相比CCI组大鼠,电针组大鼠机械痛敏值和热敏痛阈值明显提高（P<0.05, P<0.05）。电针组大鼠脊髓PAP mRNA表达和腺苷含量比CCI组大鼠显著增加（P<0.05）。与CCI组大鼠相比,电针组大鼠脊髓腺苷含量增加（P<0.01）。结论 电针可提高神经病理性痛大鼠机械痛阈值和热敏痛阈值,其机制可能是通过增加脊髓PAP mRNA的表达和腺苷含量发挥作用。     

Role of neuronal nitric oxide synthase in the antiallodynic effects of intrathecal EGCG in a neuropathic pain rat model

Epigallocatechin-3-gallate (EGCG), the major catechin in green tea, is known to have antioxidant activity against nitric oxide (NO) by scavenging free radicals, chelating metal ions, and inducing endogenous antioxidant enzymes. NO and NO synthase (NOS) play an important role in nociceptive processing. In this study, we examined the effects of intrathecal EGCG in neuropathic pain induced by spinal nerve ligation and the possible involvement of NO. Intrathecal EGCG attenuated mechanical allodynia in spinal nerve ligated-rats, compared to sham-operated rats, with a maximal possible effect of 69.2%. This antinociceptive effect was reversed by intrathecal pretreatment with l-arginine, a precursor of NO. Intrathecal EGCG also blocked the increase in nNOS expression in the spinal cord of spinal nerve-ligated rats, but iNOS expression was not significantly suppressed. These findings suggest that intrathecal EGCG could produce an antiallodynic effect against spinal nerve ligation-induced neuropathic pain, mediated by blockade of nNOS protein expression and inhibition of the pronociceptive effects of NO.     

Muscarinic receptor activation potentiates the effect of spinal cord stimulation on pain-related behavior in rats with mononeuropathy

Spinal cord stimulation (SCS) has proven to be a valuable treatment in neuropathic pain. Our previous animal experiments performed on rat models of SCS and ensuing clinical trials have demonstrated that intrathecal (i.t.) administration of subeffective doses of certain drugs may enhance the pain relieving effect of SCS in cases with unsatisfactory SCS outcome. Recently, an augmented release of spinal acetylcholine acting on muscarinic receptors has been shown to be one of the mechanisms involved in SCS. The present study was performed to examine whether cold hypersensitivity and heat hyperalgesia in rats with partial sciatic nerve injuries can be attenuated by SCS in the same way as tactile hypersensitivity and to explore a possibly synergistic effect of SCS and a muscarinic receptor agonist, oxotremorine. Rats with signs of neuropathy were subjected to SCS applied in awake, freely moving condition. Oxotremorine was administered intrathecally. Tactile, cold and heat sensitivities were assessed by using von Frey filaments, cold spray and focused radiant heat, respectively. Oxotremorine i.t. dose-dependently suppressed the tactile hypersensitivity. SCS markedly increased withdrawal thresholds (WTs), withdrawal latencies and cold scores. When combining SCS with a subeffective dose of oxotremorine i.t., the suppressive effect of SCS on the pain-related symptoms was dramatically enhanced in rats failing to obtain a satisfactory effect with SCS alone. In conclusion, the combination of SCS and a drug with selective muscarinic receptor agonistic properties could be an optional therapy, when SCS per se has proven inefficient.     

An analysis of response properties of spinal cord dorsal horn neurones to nonnoxious and noxious stimuli in the spinal rat

Summary Electrophysiological properties of neurones in the spinal cord dorsal horn were studied in decerebrated, immobilized spinal rats. Extracellular recordings were performed at the thoraco-lumbar junction level. Each track was systematically located by extracellular injection of pontamine sky blue. According to their responses to mechanical peripheral stimuli, cells were classified in four classes: Class 1 cells: Cells activated only by nonnoxious stimuli. They were divided into — 1A: hair movement and/or touch and 1B: hair movement and/or touch and pressure or pressure only. Class 2 cells: Cells driven by both nonnoxious and noxious stimuli, divided into — 2A: hair movement and/or touch, pressure, pinch and/or pin-prick, and 2B: pressure, pinch and/or pin-prick. Class 3 cells: Cells only activated by noxious stimuli (pinch and/or pin-prick). Class 4 cells: Cells responding to joint movement or pressure on deep tissues.Peripheral transcutaneous or sural nerve stimulation clearly showed that class 1 cells were activated only by A fiber input while 68% of classes 2 and 3 cells received A and C input. Histological examination indicated that cells driven only by noxious input were located either in the deepest part or in the marginal zone (lamina I) of the dorsal horn. Nevertheless, some lamina I cells were also driven by both nonnoxious and noxious stimuli. In addition, there is a great deal of overlap between class 1 and class 2 cells. This fact was confirmed by considering the wide distribution in the dorsal horn of cells receiving A and C input. However, spinal organization of the different classes of cells consists of a preferential distribution rather than a strict lamination. This study indicates that properties of dorsal horn interneurones in the rat have a high degree of similarity with those previously described in other species (cat and monkey).This work was supported by the C.N.R.S. (E.R.A. 237).     

GDF10在神经病理性疼痛大鼠脊髓中的表达

目的:观察生长和分化因子10(GDF10)在神经病理性疼痛大鼠脊髓中的表达变化。方法:取雄性SD大鼠60只,通过结扎左侧L5脊神经制备神经病理性疼痛模型,于术前1 d,术后当天及术后1 d、3 d、10 d、21d检测大鼠左后爪50%缩爪阈值,并采用免疫荧光染色及Western blot检测大鼠L5脊髓后角GDF10的表达变化。结果:脊神经结扎大鼠在术后1 d缩爪阈值开始降低,自3 d起,与正常对照组相比差异有统计学意义(P0.05),到10 d阈值下降最明显,至21 d呈现持平状态。免疫荧光检测观察到伤侧L5脊髓组织中GDF10主要表达于脊髓背角神经元细胞的胞浆内。GDF10在术后持续降低,到10 d降低最为显著,与正常组相比差异具有统计学意义(P0.05),一直持续低水平表达至21 d。Western blot证实术后10 d脊髓中GDF10蛋白的表达较正常组大鼠明显降低(P0.05)。结论:大鼠脊神经结扎使脊髓背角中GDF10表达减少,其减少可能与大鼠脊神经损伤后对机械刺激引起的疼痛过敏有关联。